Systems and methods for distraction

ABSTRACT

A system for moving a portion of a patient&#39;s body including a housing having a first cavity extending along a longitudinal axis, a first distraction rod having a proximal end and a distal end, the first distraction rod and the housing being telescopically displaceable with respect to each other along the longitudinal axis, the first distraction rod having a cavity extending along the longitudinal axis, a second distraction rod having a proximal end and a distal end and configured to be telescopically displaceable from within the second cavity along the longitudinal axis, and a drive system configured to move the first distraction rod in relation to the housing and to move the second distraction rod in relation to the first distraction rod.

BACKGROUND

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57.

Scoliosis is a general term for the sideways (lateral) curving of thespine, usually in the thoracic or thoracolumbar region. Scoliosis iscommonly broken up into different treatment groups, AdolescentIdiopathic Scoliosis, Early Onset Scoliosis and Adult Scoliosis.

Adolescent Idiopathic Scoliosis (AIS) typically affects children betweenages 10 and 16, and becomes most severe during growth spurts that occuras the body is developing. One to two percent of children between ages10 and 16 have some amount of scoliosis. Of every 1000 children, two tofive develop curves that are serious enough to require treatment. Thedegree of scoliosis is typically described by the Cobb angle, which isdetermined, usually from x-ray images, by taking the most tiltedvertebrae above and below the apex of the curved portion and measuringthe angle between intersecting lines drawn perpendicular to the top ofthe top vertebrae and the bottom of the bottom. The term idiopathicrefers to the fact that the exact cause of this curvature is unknown.Some have speculated that scoliosis occurs when, during rapid growthphases, the ligamentum flavum of the spine is too tight and hinderssymmetric growth of the spine. For example, as the anterior portion ofthe spine elongates faster than the posterior portion, the thoracicspine begins to straighten, until it curves laterally, often with anaccompanying rotation. In more severe cases, this rotation may actuallycreate a noticeable deformity, wherein one shoulder is lower than theother. Currently, many school districts perform external visualassessment of spines, for example in all fifth grade students. For thosestudents in whom an “S” shape or “C” shape is identified, instead of an“I” shape, a recommendation is given to have the spine examined by aphysician, and commonly followed-up with periodic spinal x-rays.

Typically, patients with a Cobb angle of 20° or less are not treated,but are continually monitored, often with subsequent x-rays. Patientswith a Cobb angle of 40° or greater are frequently candidates for fusionsurgery. It should be noted that many patients do not receive such aspinal assessment, for numerous possible reasons. Many school districtsdo not perform this simple assessment, and many children do notregularly visit a physician. Therefore, the curve often progressesrapidly and severely. There is a large population of grown adults withuntreated scoliosis, some having extreme cases exhibiting Cobb angles of90° or greater. Many adults having untreated scoliosis, though, do nothave pain associated with their deformity and live relatively normallives, though oftentimes with restricted mobility and motion. In AIS,the ratio of females to males having Cobb angles under 10° is about oneto one. However, at Cobb angles above 30°, females outnumber males by asmuch as eight to one. Fusion surgery can be performed on the AISpatients or on adult scoliosis patients. In a typical posterior fusionsurgery, an incision is made down the length of the back and Titanium orstainless steel straightening rods are placed along the curved portion.These rods are typically secured to the vertebral bodies, for examplewith hooks or bone screws, or more specifically pedicle screws, in amanner that allows the spine to be straightened. Usually, at the sectionselected for fusion, the intervertebral disks are removed and bone graftmaterial is placed to create the fusion. If autologous graft material isused, the bone is generally harvested from a hip via a separateincision.

Alternatively, fusion surgery may be performed anteriorly. A lateral andanterior incision is made for access. Usually, one of the lungs isdeflated in order to allow access to the spine from this anteriorapproach. In a less-invasive version of the anterior procedure, insteadof the single long incision, approximately five incisions, each aboutthree to four cm long are made in several of the intercostal spaces(between the ribs) on one side of the patient. In one version of thisminimally invasive surgery, tethers and bone screws are placed andsecured to the vertebra on the anterior convex portion of the curve.Currently, clinical trials are being performed in which staples are usedinstead of the tether/screw combination. One advantage of this surgeryin comparison with the posterior approach is that scars resulting fromthe several smaller incisions are not as dramatic, though they are stilllocated in a visible area, when a bathing suit, for example, is worn.Staple-based techniques have experienced some difficulty in clinicaltrials. The staples tend to pull out of the bone when a critical stresslevel is reached.

In some cases, after surgery, the patient will wear a protective bracefor a few months as the fusing process occurs. Once the patient reachesspinal maturity, it may be difficult to remove the rods and associatedhardware in a subsequent surgery because the fusion of the vertebrausually incorporates the rods themselves. Therefore, standard practiceis to leave this implant in for life. With either of these two surgicalmethods, after fusion the patient's spine is rendered straight, but,depending on the number of vertebrae that were fused, limitations in thedegree of flexibility, both in bending and twisting, are often observed.As fused patients mature, the fused section of the spine can impartsignificant stresses on the adjacent non-fused vertebrae, and often,other problems including pain can occur in these areas, sometimesnecessitating further surgery. This tends to be in the lumbar portion ofthe spine that is prone to problems in aging patients. Many physiciansare now interested in fusionless surgery for scoliosis, which may beable to eliminate, or at least reduce, one or more of the drawbacks offusion.

One group of patients in which the spine is especially dynamic is thesubset known as Early Onset Scoliosis (EOS), which typically occurs inchildren before the age of five, and more often in boys than in girls.EOS is a more rare condition than AIS, occurring in only about one ortwo out of 10,000 children, but can be severe, sometimes affecting thenormal development of organs. Because the spines of these children willgenerally grow a large amount after treatment, non-fusion distractiondevices known as growing rods and a device known as the VEPTR—VerticalExpandable Prosthetic Titanium Rib (“Titanium Rib”) have been developed.These devices are typically adjusted approximately every six months, oras required to match the child's growth, until the child is at leasteight years old, and sometimes until they are 15 years old. Eachadjustment requires a surgical incision to access the adjustable portionof the device. Because the patients may receive the device at an age asearly as six months old, this treatment may require a large number ofsurgeries. Because of the multiple surgeries, these patients have arather high incidence of infection.

Returning to the AIS patients, the treatment methodology for those witha Cobb angle between 20° and 40° is quite controversial. Many physiciansprescribe a brace (for example, the Boston Brace) for a patient to wearon his body, under the clothes, 18 to 23 hours a day until the patientbecome skeletally mature (e.g., age 16). Because these patients are allpassing through their socially demanding adolescent years, it is a quiteserious prospect to choose between wearing a somewhat bulky brace thatcovers most of the upper body, having fusion surgery that may leavelarge scars and limit motion, and doing nothing and risking becomingdisfigured and possibly disabled. It is common knowledge that manypatients have, at times, hidden their braces, for example, in a bushoutside of school, in order to escape embarrassment associated with thebrace(s). The patient compliance with brace wearing has been soproblematic that special braces have been constructed that sense thebody of the patient and keep track of the amount of time per day thatthe brace is worn. Even such special braces have problems with patientcompliance: patients have been known to place objects into unworn bracesof this type in order to fool the sensor. Coupled with the inconsistentpatient compliance with brace usage, is a feeling by many physiciansthat braces, even if used properly, are not at all effective at curingscoliosis. Physicians may agree that bracing can possibly slow down oreven temporarily arrest curve (Cobb angle) progression, but they havenoted that as soon as the treatment period ends and the brace is nolonger worn, often the scoliosis progresses rapidly to a Cobb angle evenmore severe than it was at the beginning of treatment. Some say thereason for the supposed ineffectiveness of the brace is that it bracesonly on a portion of the torso, and not on the entire spine. Currently aprospective, randomized, 500-patient, clinical trial known as BrAIST(Bracing in Adolescent Idiopathic Scoliosis Trial) is enrollingpatients, 50% of whom will be treated with the brace and 50% of who willsimply be watched. Cobb angle data from these patients will be measuredcontinually up until they reach skeletal maturity, or until a Cobb angleof 50° is reached, at which time the patient will likely undergosurgery. Many physicians feel that the BrAIST trial will show thatbraces are completely ineffective. If this is the case, the quandaryabout what to do with AIS patients who have a Cobb angle of between 20°and 40° will only become more pronounced. It should be noted that thepatient population having a Cobb angle of 20-40° is as much as ten timeslarger than the population having a Cobb angle of 40° and greater.

Distraction osteogenesis, also known as distraction callotasis andosteodistraction has been used successfully to lengthen various bones ofthe body (e.g., long bones). Typically, the bone, if not alreadyfractured, is purposely fractured by means of a corticotomy, and theresulting two segments of bone are gradually distracted apart, therebyallowing new bone to form in the gap. If the distraction rate is toohigh, there is a risk of nonunion. If the rate is too low, there is arisk that the two segments will prematurely, fuse to each other morethan desired before the distraction period is complete. Once the desiredlength of the bone is achieved using this process, the bone is allowedto consolidate. Distraction osteogenesis applications are mainly focusedon the growth of the femur or tibia, but may also include the humerus,the jaw bone (micrognathia), or other bones. There are many reasons forlengthening or growing bones which may be desirable. The applicationsincluding, but not limited to: post osteosarcoma bone cancer; cosmeticlengthening (both legs-femur and/or tibia) in short stature ordwarfism/achondroplasia; lengthening of one limb to match the other(congenital, post-trauma, post-skeletal disorder, prosthetic kneejoint), nonunions.

Distraction osteogenesis using external fixators has been done for manyyears, but the external fixator can be unwieldy and painful for thepatient. It can also subject the patient to the risk of pin trackinfections, joint stiffness, loss of appetite, depression, cartilagedamage and other side effects. An external fixator, e.g., around thepatient/patient's limb, can also delay the beginning of rehabilitation.

In response to the shortcomings of external fixator distraction,intramedullary distraction nails which may be contained entirely withinthe bone have been surgically implanted. Some such nails may beautomatically lengthened via repeated rotation of the patient's limb,which can sometimes be painful to the patient, and can often proceed inan uncontrolled fashion. This therefore makes it difficult to follow thestrict daily or weekly lengthening regime that avoids nonunion (if toofast) or early consolidation (if too slow). Lower limb distraction ratesare generally on the order of about one mm per day. Other intramedullarynails which have an implanted motor and may be remotely controlled by anantenna have also been developed. These devices are designed to belengthened or distracted in a controlled manner, but, due to theircomplexity, may not be manufacturable as an affordable product. Othershave proposed intramedullary distractors containing an implanted magnet,which allows the distraction to be driven electromagnetically by anexternal stator. Because of the complexity and size of the externalstator, this technology has not been reduced to a simple and/orcost-effective device, which can be taken home to allow patients to dodaily lengthenings. Non-invasively adjustable implantable distractiondevices, at least one embodiment of which is magnetically non-invasivelyadjustable, have been developed and used clinically in both scoliosisand limb lengthening patients.

Knee osteoarthritis is a degenerative disease of the knee joint thataffects a large number of patients, particularly over the age of 40. Theprevalence of this disease has increased significantly over the lastseveral decades, attributed partially, but not completely, to the risingage of the population as well as the increase in obesity. The increasemay also be due to an increase in highly active people within thepopulation. Knee osteoarthritis is caused mainly by long term stresseson the knee that degrade the cartilage covering the articulatingsurfaces of the bones in the knee joint. Oftentimes, the problem becomesworse after a particular trauma event, but it can also be a hereditaryprocess. Symptoms include, but are not limited to, pain, stiffness,reduced range of motion, swelling, deformity, and muscle weakness.Osteoarthritis may include one or more of the three compartments of theknee: the medial compartment of the tibiofemoral joint, the lateralcompartment of the tibiofemoral joint, and the patellofemoral joint. Insevere cases, partial or total replacement of the knee is performed inorder to replace the diseased portions with new weight bearing surfacesfor the knee, typically made from implant grade plastics or metals.These operations may involve significant post-operative pain and requiresubstantial physical therapy. The recovery period may last weeks ormonths. Several potential complications of this surgery exist, includingdeep venous thrombosis, loss of motion, infection, and bone fracture.After recovery, surgical patients who have received uni-compartmental ortotal knee replacement must significantly reduce their activity,removing running and high energy sports completely from their lifestyle.

For these reasons, surgeons are attempting to intervene early in orderto delay or even preclude knee replacement surgery. Osteotomy surgeriesmay be performed on the femur or tibia, in order to change the anglebetween the femur and tibia, and thus adjust the stresses on thedifferent portions of the knee joint. In closed wedge or closing wedgeosteotomy, an angled wedge of bone is removed, and the remainingsurfaces are fused together, creating a new improved bone angle. In openwedge osteotomy, a cut is made in the bone and the edges of the cut areopened, creating a new angle. Bone graft is often used to fill in thenewly-opened, wedge-shaped space, and, often, a plate is attached to thebone with bone screws. Obtaining the correct angle during either ofthese types of osteotomy is almost always difficult, and, even if thefinal result is close to what was desired, there can be a subsequentloss of the correction angle. Some other complications associated withthis technique include nonunion and material failure.

Amputation of the arm or the leg can result in a residual limb, with astump, having a shortened bone (e.g., a shortened femur, tibia, fibula,humerus, radius or ulna). A prosthetic limb or prosthetic limbattachment which may be attached to a residual limb may have problemsfitting or functioning when attached to a residual limb havinginsufficient bone length. There may be poor energy transfer between theresidual limb and the attached prosthesis, as short lever arms generateless torque for a given force. This functional deficit is compoundedwhen the lever arm is encased in very compliant tissue, such as aresidual femur that is surrounded by the soft tissues of the thigh. Thismay further impair prosthesis control. Individuals having short residuallimbs may display gait asymmetries and gait changes. The wearer of aprosthetic limb who has a relatively short residual limb may exhibitcompensatory changes that affect posture and cause discomfort or injuryto the spine or other body structures. Amputation may occur or may beperformed for several reasons including war-related injuries, motorvehicle accidents, including motorcycle accidents, other types of traumaor cancer of the bone or other adjacent tissue.

In addition to the many different types of implantable distractiondevices that are configured to be non-invasively adjusted, implantablenon-invasively adjustable non-distraction devices have also beenenvisioned, for example, adjustable restriction devices forgastrointestinal disorders such as GERD, obesity, or sphincter laxity(such as in fecal incontinence), or other disorders such as sphincterlaxity in urinary incontinence. These devices, too, may incorporatemagnets to enable non-invasive adjustment.

SUMMARY

The present disclosure provides for a system for moving a portion of apatient's body including a housing having a first cavity extending alonga longitudinal axis, a first distraction rod having a proximal end and adistal end and configured to be telescopically displaceable from withinthe first cavity along the longitudinal axis, the first distraction rodhaving a second cavity extending along the longitudinal axis, a seconddistraction rod having a proximal end and a distal end and configured tobe telescopically displaceable from within the second cavity along thelongitudinal axis, and a drive system configured to move the firstdistraction rod in relation to the housing and to move the seconddistraction rod in relation to the first distraction rod.

The present disclosure further provides for a method of modifying aresidual limb of a patient including the steps of providing adistraction device having a housing extending along a longitudinal axis,a first distraction rod having a proximal end and a distal end, thefirst distraction rod and the housing being telescopically displaceablewith respect to each other along the longitudinal axis, the firstdistraction rod having a cavity extending along the longitudinal axis, asecond distraction rod having a proximal end and a distal end and beingconfigured to be telescopically displaceable from within the cavityalong the longitudinal axis, and a drive system configured to move thefirst distraction rod in relation to the housing and to move the seconddistraction rod in relation to the first distraction rod, attaching thehousing to a first portion of a bone within the residual limb, attachingthe second distraction rod to a second portion of the bone within theresidual limb, decoupling the first portion of the bone from the secondportion of the bone, and wherein the distraction device is actuatablesuch that the first distraction rod is caused to move in relation to thehousing and the second distraction rod is caused to move in relation tothe first distraction rod, to increase at least one of a force or adistance between the first portion of the bone and the second portion ofthe bone.

The present disclosure further provides for a system for moving aportion of a patient's body including a housing having a first cavityextending along a longitudinal axis, a first distraction rod having aproximal end and a distal end, the first distraction rod and the housingbeing telescopically displaceable with respect to each other along thelongitudinal axis, the first distraction rod having a cavity extendingalong the longitudinal axis, a second distraction rod having a proximalend and a distal end and configured to be telescopically displaceablefrom within the second cavity along the longitudinal axis, and a drivesystem configured to move the first distraction rod in relation to thehousing and to move the second distraction rod in relation to the firstdistraction rod.

In one embodiment, a system for moving a portion of a patient's body isprovided. The system for moving a portion of a patient's body includes:a housing having a first cavity extending along a longitudinal axis; afirst distraction rod having a proximal end, a distal end, and a secondcavity extending between the proximal end and the distal end, and beingconfigured for telescopic displacement from within the first cavity; asecond distraction rod having a proximal end and a distal end, and beingconfigured for telescopic displacement from within the second cavity;and a drive system configured to move at least one of the firstdistraction rod and the second distraction rod.

In one embodiment, a method of modifying a residual limb is provided.The method of modifying a residual limb of a patient includes the stepsof: providing a distraction device comprising: a housing extending alonga longitudinal axis; a first distraction rod having a proximal end and adistal end, the first distraction rod and the housing beingtelescopically displaceable with respect to each other, the firstdistraction rod having a cavity extending along the longitudinal axis; asecond distraction rod having a proximal end and a distal end andconfigured to be telescopically displaceable from within the cavity; anda drive system configured to move at least one of the first distractionrod in relation to the housing and the second distraction rod inrelation to the first distraction rod; decoupling the first portion ofthe bone from the second portion of the bone; attaching the housing to afirst portion of a bone within the residual limb; attaching the seconddistraction rod to a second portion of the bone within the residuallimb, wherein the distraction device is actuatable such that the firstdistraction rod is caused to move in relation to the housing and thesecond distraction rod is caused to move in relation to the firstdistraction rod, to increase at least one of a force or a distancebetween the first portion of the bone and the second portion of thebone.

In another embodiment, a system for moving a portion of a patient's bodyis provided. The system for moving a portion of a patient's bodyincludes: a housing having a first cavity extending along a longitudinalaxis; a first distraction rod having a proximal end, a distal end, and acavity extending along the longitudinal axis, the first distraction rodand the housing being telescopically displaceable with respect to eachother along the longitudinal axis; a second distraction rod having aproximal end and a distal end, and configured to be telescopicallydisplaceable from within the second cavity along the longitudinal axis;a drive system configured to move the first distraction rod in relationto the housing and to move the second distraction rod in relation to thefirst distraction rod.

In still another embodiment, a system for moving a portion of apatient's body is provided. The system for moving a portion of apatient's body includes: a housing having a first cavity; a firstdistraction rod having a proximal end, a distal end, and a secondcavity, wherein the first distraction rod is configured for telescopicdisplacement relative to the first cavity; a second distraction rodhaving a proximal end and a distal end, wherein the second distractionrod is configured for telescopic displacement from within the secondcavity; and a drive system configured to move at least one of the firstdistraction rod and the second distraction rod.

In one embodiment, a method of modifying a residual limb of a patient isprovided. The method of modifying a residual limb includes the steps of:providing a distraction device comprising: a housing having a firstcavity; a first distraction rod having a proximal end, a distal end, anda second cavity, wherein the first distraction rod is telescopicallydisplaceable relative to the first cavity; a second distraction rodhaving a proximal end and a distal end, wherein the second distractionrod is telescopically displaceable from within the second cavity; and adrive system configured to move at least one of the first distractionrod and the second distraction rod with respect to the housing; thendecoupling a first portion of a bone within the residual limb from asecond portion of the bone; attaching the housing to one of the firstportion and the second portion of the bone within the residual limb; andattaching the second distraction rod to the other of the first portionand the second portion of the bone within the residual limb, wherein thedrive system is configured to be actuated so as to increase at least oneof a force and a distance between the first portion and the secondportion of the bone.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a distraction device.

FIG. 2 illustrates the distraction device of FIG. 1 in a partiallydistracted configuration.

FIG. 3 illustrates the distraction device of FIG. 1 in a fullydistracted configuration.

FIG. 4 illustrates an exploded view of a distraction device.

FIG. 5 illustrates an elevation view of a distraction device.

FIG. 6 illustrates a sectional view of the distraction device of FIG. 5taken along line 6-6.

FIG. 7 illustrates a residual limb.

FIG. 8 illustrates a distraction device inserted within a medullarycanal of a bone of a residual limb.

FIG. 9 illustrates a distraction device secured within a medullary canalof a bone of a residual limb.

FIG. 10 illustrates an example external remote controller for wirelesslycontrolling and communicating with an implantable device.

FIG. 11 illustrates the internal components of a handpiece of theexternal remote controller of FIG. 10 .

FIG. 12 illustrates a distraction device and residual limb after partialdistraction.

FIG. 13 illustrates a distraction device and residual limb after fulldistraction.

FIG. 14 illustrates a distraction device as disclosed herein placed nextto a distraction device already in the prior art.

FIG. 15 illustrates a sectional view of the distraction device of FIG.14 taken along line 15-15.

FIG. 16 illustrates the distraction device of FIGS. 14 and 15 in apartially distracted configuration.

FIG. 17 illustrates a sectional view of the distraction device of FIG.16 taken along line 17-17.

FIG. 18 illustrates the distraction device of FIGS. 14-17 in a fullydistracted configuration.

FIG. 19 illustrates a sectional view of the distraction device of FIG.18 taken along line 19-19.

FIGS. 20-23 schematically illustrate various alternate sources of adriving element of a non-invasively adjustable spinal implant.

FIG. 24 illustrates a kit containing instruments for use withdistraction devices according to embodiments described herein.

DETAILED DESCRIPTION

Embodiments of the adjustable devices for implanting into the bodydisclosed herein are capable of achieving a large (e.g., greater than40%, greater than, greater than 60%, greater than 80%, greater than 100%and even greater than 120%) total amount of adjustment length incomparison to the total length of the adjustable portion of the device.Adjustable devices may include distraction devices, for exampledistraction devices for orthopedic applications, including, but notlimited to scoliosis, limb lengthening, bone transport, spinous processdistraction, tibial wedge osteotomy adjustment, and spondylolisthesis.Maintaining a small size an adjustable (e.g., distraction and/orretraction) implant to fit into a small, short space within the body,and achieving large amounts of adjustable length have historically beenconflicting design goals.

FIGS. 1-3 illustrate an embodiment of an implantable adjustable system100 comprising a distraction device 110. The distraction device 110comprises a housing 202, a first distraction rod 204 and a seconddistraction rod 206. The second distraction rod 206 and the housing 202are each configured for coupling to a patient. The second distractionrod 206 contains one or more holes 208 for passing an anchor with whichto secure the distraction device 110 to a patient. One of the one ormore holes 208 may be located between about 3 mm and 15 mm, orapproximately 5 mm, from the distal end of the second distraction rod206. The housing 202 contains one or more holes 210 for passing ananchor with which to secure the distraction device 110 to the patient.One of the one or more holes 210 may be located between about 5 mm andabout 20 mm, or approximately 10 mm, from the proximal end of thehousing 202. The housing 202 may have a diameter of between about 8.5 mmand about 16 mm, or between about 10.5 mm and about 14.5 mm, or about 14mm. In some embodiments, the anchor is a bone anchor, for example, abone screw 224, 226 (FIG. 4 ). The bone screws 224, 226 may be betweenabout 3 mm and about 6 mm in diameter. In some embodiments, bone screw244 is 4 mm in diameter and bone screw 226 is 5 mm in diameter. The bonescrews may be between about 18 mm and about 80 mm in length, or betweenabout 20 mm and about 75 mm in length. However, other types of anchoringand/or connection are contemplated for coupling the second distractionrod 206 and the housing 202 to the bone of the patient. As illustratedin FIG. 2 , the second distraction rod 206 may be configured to betelescopically displaceable with respect to the housing 202. As seen inFIG. 2 , the second distraction rod 206 may be configured to also betelescopically displaceable with respect to the first distraction rod204. As illustrated in FIG. 3 , the first distraction rod 204 may beconfigured to be telescopically displaceable with respect to the housing202. The first distraction rod 204 may be longitudinally displaceablefrom within a cavity 212 in the housing 202 that extends alonglongitudinal axis Z (FIG. 1 ). The first distraction rod 204 may beconfigured to be telescopically displaceable along the longitudinal axisZ. The first distraction rod 204 has a cavity 214, with the seconddistraction rod 206 configured to telescopically displace from thecavity 214 along the longitudinal axis Z. In some embodiments, the firstdistraction rod 204 may have a diameter of between about 8 mm and about13 mm, or about 11.5 mm. In some embodiments, the second distraction rod206 may have a diameter of between about 5 mm and about 11 mm, or about9 mm. In some embodiments it may be desired that there be no rotationalmotion (about the longitudinal axis Z) between at least one of thehousing 202, the first distraction rod 204, and the second distractionrod 206. In some embodiments, one or more first longitudinal grooves 216extends along an exterior surface 218 of the first distraction rod 204and is slidingly engaged by protrusions 209 (FIG. 4 ) which extend in aninward radial direction from the interior of a cap 215, which is coupledto the housing 202, thus allowing longitudinal displacement between thefirst distraction rod 204 and the housing 202, but not allowing rotationbetween them. External ribs 217 on the cap 215 insert into grooves 219in the housing 202 during assembly. The cap 215 may be snapped intoplace on the housing 202 or otherwise secured by adhesive, welding,soldering, brazing or other methods. One or more second longitudinalgrooves 220 extending along an exterior surface 222 of the seconddistraction rod 206 are slidingly engaged by protrusions 211 (FIG. 4 )which extend from the interior of the cavity 214 of the firstdistraction rod 204 in an inward radial direction, thus allowinglongitudinal displacement between the second distraction rod 206 and thefirst distraction rod 204, but not allowing rotation between them. Ifthe distraction device 110 is used for the purpose of distracting twopieces of bone (e.g., move two bones or two pieces of a bone apart fromeach other), then the protrusions 209, 211 and longitudinal grooves 216,220 make it possible to assure that there may be substantially norotation between the two bone pieces. As seen in FIG. 3 , the firstlongitudinal grooves 216 and the second longitudinal grooves 220 can bepurposely configured to reside at different clock positions (incircumferential relation to the longitudinal axis Z (FIG. 1 ), in orderto make enough room in the second distraction rod 206, the firstdistraction rod 204, and the housing 202, so that wall thickness, andthus strength and durability, are not compromised.

Turning to FIG. 4 , bone screws 224, 226 are depicted having unicorticalthreads 228, 230 and unthreaded shafts 232, 234, however, any type ofbone screw, for example a fully-threaded bone screw, may be used forplacement through the holes 208, 210. The holes 208, 210 may beperpendicular to the longitudinal axis Z, or may be at various angles,depending upon the configuration through which they are to be coupled tothe bone. With further reference to FIGS. 4-6 , the distraction device110 comprises a driving element 242 configured to be activated by aremotely applied source. A nut 236 may be secured within a cavity 238 inthe second distraction rod 206. The nut 236 may have external threads240, which are engaged or bonded into an internal thread 244 of thecavity 238. The nut 236 also contains an internal thread 246. A magneticassembly 248 may be held between a radial bearing 250 and a thrustbearing 252 (FIG. 6 ), and comprises a radially-poled permanent magnet338 which is rotationally coupled to one or more gear modules 256 (e.g.,planetary gearing). The thrust bearing 252 and radial bearing 250 may berestrained at their longitudinal extents in relation to the housing 202,in order to maintain the magnetic assembly 248 within the housing 202,while allowing it and its components to rotate freely. In someembodiments, the permanent magnet 338 may be carried within one or morecylindrical housings or cups. The one or more gear modules 256 output(through the interior of the thrust bearing 252) to a coupler 258, whichmay be rotationally coupled to a first lead screw 260 via a pin 262,which passes through a hole 261 in the coupler 258 and a hole 263 at aproximal end 264 of the first lead screw 260. The first lead screw 260also has an abutment 270 at its distal end 266, and comprises anexternal thread 268. In some embodiments, the gear modules 256 mayprovide a gear ratio of 4:1, 16:1, 64:1, 256:1 between the magnet 338and the first lead screw 260, or another ratio. In some embodiments, thefirst lead screw 260 may be directly coupled to the magnet 338, and thusprovide 1:1 rotation. The first lead screw 260 may be threadinglyengaged with an internal thread 272 of a second lead screw 274. Themajority of the length of the second lead screw 274 may be an internalbore 271 with a diameter that is equal to or greater than the majordiameter of the internal thread 272. The internal thread 272 may belocated only at the proximal end 275 of the second lead screw 274. Insome embodiments, the length of the internal thread 272 along thelongitudinal axis Z may be about 3 mm to about 7 mm, or about 5.5 mm.The external thread 276 of the second lead screw 274 may be threadinglyengaged with the internal thread 246 of the nut 236 which may be securedwithin the second distraction rod. An exemplary external threadspecification for each of the lead screws 260, 274 may be 80 threads perinch.

The interior contents of the distraction device 110, including theinterior portions of cavities 212, 214, 238, which contain the magneticassembly 248 and the lead screws 260, 274, are protected from externalfluids and materials by dynamic seals 278, 280. A first dynamic seal 278includes an o-ring 282, which resides within a circumferential groove284 at a proximal end 286 of the first distraction rod 204. The o-ring282 seals along an inner cylindrical surface 288 of the housing 202, andmaintains the dynamic seal 278 throughout the longitudinal displacementof the first distraction rod 204 with the housing 202. A second dynamicseal 280 includes an o-ring 290, which resides within a circumferentialgroove 292 at a proximal end 294 of the second distraction rod 206. Theo-ring 290 seals along an inner cylindrical surface 296 of the firstdistraction rod 204, and maintains the dynamic seal 280 throughout thelongitudinal displacement of the second distraction rod 206 with thefirst distraction rod 204.

FIG. 6 illustrates the distraction device 110 in a fully undistracted(or retracted) condition, wherein the distal end 287 of the firstdistraction rod 204 and the distal end 295 of the second distraction rod206 are located near the distal end 203 of the housing 202. In use, whenthe magnet 338 is rotated (e.g., by an externally-applied movingmagnetic field) (and caused to rotate in a first rotational direction)the first lead screw 260 may be turned (through the gear ratios of gearmodules 256A, 256B, 256C). The turning of the external thread 268 of thefirst lead screw 260 in relation to the internal thread 272 of thesecond lead screw 274, thus causes both the second distraction rod 206and the second lead screw 274 to longitudinally extend from the housing202. As described, in at least some embodiments, the second distractionrod 206 is prevented from rotation with respect to the first distractionrod 204 and the housing 202. In some embodiments, the second lead screw274 does not turn as it longitudinally extends with the seconddistraction rod 206, thus the first distraction rod 204 does notlongitudinally extend in relation to the housing 202. FIG. 12 , whichwill be referred to later when describing the procedure for lengtheninga bone in a residual limb, shows the distraction rod 110 after thesecond distraction rod 206 has been longitudinally extended in relationto both the housing 202 and the first distraction rod 204. For thisfirst stage of distraction to occur as described, the frictional torquebetween the external thread 268 of the first lead screw 260 and theinternal thread 272 of the second lead screw 274 is less than thefrictional torque between the external thread 276 of the second leadscrew 274 and the internal thread 246 of the nut 236. This tends to bethe case, however, other assembly steps and materials may additionallybe provided in order to assure this. For example, in some embodiments, asilicone lubricant or a Krytox® lubricant may be applied to the externalthread 268 of the first lead screw 260 and/or the internal thread 272 ofthe second lead screw 274, but not to the external thread 276 of thesecond lead screw 274 and the internal thread 246 of the nut 236. Insome embodiments, the lubricant may be applied more liberally to theexternal thread 268 of the first lead screw 260 and/or the internalthread 272 of the second lead screw 274 than to the external thread 276of the second lead screw 274 and/or the internal thread 246 of the nut236. In some embodiments, a more lubricious lubricant may be applied tothe external thread 268 of the first lead screw 260 and/or the internalthread 272 of the second lead screw 274 while a less lubriciouslubricant is applied to the external thread 276 of the second lead screw274 and/or the internal thread 246 of the nut 236.

The longitudinal length of distraction possible for the seconddistraction rod 206 on its own may be between about 20 mm and about 90mm, or between about 40 mm and about 70 mm, or about 50 mm. When thesecond distraction rod 206 has been fully distracted in relation to thefirst distraction rod 204, the first lead screw 260 will rotationallyengage with the second lead screw 274, and thus the rotation of thefirst lead screw 260 will begin to turn the second lead screw 274 (e.g.,in a one-to-one manner). In some embodiments, this occurs when theabutment 270 at the distal end 266 of the first lead screw 260 contactsa ledge 273 adjacent the internal thread 272 at the proximal end 275 ofthe second lead screw 274. As the first lead screw 260 continues to turnthe second lead screw 274, the external thread 276 of the second leadscrew 274 turns inside the internal thread 246 of the nut 236 of thesecond distraction rod 206, causing the second distraction rod 206 tolongitudinally extend further in relation to the housing 202, but now,while also dragging the first distraction rod 204 along with it. Thelongitudinal length of distraction possible for the first distractionrod 204, after full distraction of the second distraction rod 206, maybe between about 20 mm and about 90 mm, or between about 40 mm and about70 mm, or about 50 mm. FIG. 13 shows the distraction rod 110 after thefirst distraction rod 204 and the second distraction rod 206 have beenlongitudinally extended in this manner in relation to the housing 202.Using this two-stage approach to distraction, a total distraction lengthof 100 mm, or even greater than 100 mm, may be possible with a housing202 having a cavity 212 length of only 97 mm; thus the distractionlength provided can be 102% of the housing cavity length. In someembodiments, the length of the distraction device 110 is 130 mm in afully retracted state and 230 mm in a fully distracted state. Prior artdevices that use only a single distraction rod generally providedistraction lengths of only 40% to 50% of the housing cavity length. Thedistraction device 110 may be also capable of retracting, by applying amoving magnetic field in an opposite direction, and causing thecomponents to turn in opposite directions.

In some embodiments, the distraction device 110 (FIG. 4 ) may includefeatures to limit the extent of distraction of the second distractionrod 206 in relation to the first distraction rod 204, and in the firstdistraction rod 204 in relation to the housing 202. For example, anabutment 289, or stop, may be located at the end of the longitudinalgroove 216, or at another location at the proximal end 286 of the firstdistraction rod 204. An abutment 291, or stop, may be located at adistal, internal portion of the housing 202, For example, wherein theabutment 291 is a protrusion carried on the internal wall of the housing202, or wherein it is a one end of the protrusion 209 of the cap 215.The abutment 291 may be configured to abut/engage the abutment 289 at amaximum degree of extension of the first distraction rod 204 in relationto the housing 202. Furthermore, an abutment 293, or stop, may belocated at the end of the longitudinal groove 220, or at anotherlocation at the proximal end 294 of the second distraction rod 206. Anabutment 297, or stop, may be located at a distal, internal portion ofthe first distraction rod 204, for example, wherein the abutment 297 isa protrusion carried on the internal wall of the first distraction rod204. The abutment 297 may be configured to abut/engage the abutment 293at a maximum degree of extension of the second distraction rod 206 inrelation to the first distraction rod 204. Each of the abutments 289,291, 293, 297 may be configured so that the second distraction rod 206,the first distraction rod 204, and the housing 202 do not get stuck orjammed against each other when the longitudinal extents are reached,thus allowing for retraction or shortening of the distraction device110, if desired. The shortening of the distraction device 110 may bedesired in certain situations in which compression of bone pieces isneeded. This includes situations in which it is desired to form, reform,or improve a callus for osteogenesis. In some embodiments, theprotrusions 209, 211 themselves may serve as the abutments 291, 297.

The implantable adjustable system 100 incorporating a distraction device110, as disclosed herein, may utilize an External Remote Controller(ERC). FIG. 10 illustrates an example of an External Remote Controller(ERC) 180 which may be used to non-invasively control the distractiondevice 110 by means of a magnetic coupling of torque. ERC 180 comprisesa magnetic handpiece 178, a control box 176 (containing a processor)which may be integrated with the handpiece 178 and a power supply 174such as a battery or external plug for connection to a standard poweroutlet. The control box 176 includes a control panel 182 having one ormore controls (buttons, switches or tactile, motion, audio or lightsensors) and a display 184. The display 184 may be visual, auditory,tactile, the like, or some combination of the aforementioned features,or any other display/UI described in this disclosure. The control box176 may further contain a transceiver for communication with atransceiver in the implant and/or other external devices.

FIG. 11 illustrates an internal assembly 478 of the magnetic handpiece178 configured for applying a moving magnetic field to allow fornon-invasive adjustment of the distraction device 110 by turning themagnet 338 within the distraction device 110. The magnet 338 of thedistraction device 110 includes a north pole 406 and a south pole 408. Amotor 480 with a gear box 482 outputs to a motor gear 484. The motorgear 484 engages and turns a central (idler) gear 486, which has theappropriate number of teeth to turn first and second magnet gears 488,490 at identical rotational speeds. First and second magnets 492, 494turn in unison with the first and second magnet gears 488, 490,respectively. Each magnet 492, 494 may be held within a respectivemagnet cup 496 (shown partially). An exemplary rotational speed may be60 RPM or less. This speed range may be desired in order to limit theamount of current density included in the body tissue and fluids, tomeet international guidelines or standards. As seen in FIG. 11 , thesouth pole 498 of the first magnet 492 may be oriented the same as thenorth pole 404 of the second magnet 494, and likewise, the first magnet492 has its north pole 400 oriented the same and the south pole 402 ofthe second magnet 494. As these two magnets 492, 494 turn synchronouslytogether, they apply a complementary and additive moving magnetic fieldto the radially-poled, magnet 338. Magnets having multiple north poles(for example, two) and multiple south poles (for example, two) are alsocontemplated in each of the devices. Alternatively, a single magnet(e.g., a magnet with a larger diameter) may be used in place of the twomagnets. As the two magnets 492, 494 turn in a first rotationaldirection 410 (e.g., counter-clockwise), the magnetic coupling causesthe magnet 338 to turn in a second, opposite rotational direction 412(e.g., clockwise). The rotational direction of the motor 480 may becontrolled by buttons 414, 416. One or more circuit boards 418 containcontrol circuitry for both sensing rotation of the magnets 492, 494 andcontrolling the rotation of the magnets 492, 494.

FIGS. 7-9 and 12-13 illustrate the implantable adjustable system 100incorporating a distraction device 110 and an External Remote Controller(ERC) 180 being used in a surgery and subsequent adjustment proceduresto increase the length of a bone 502 in a residual limb 500. In somecases, the residual limb is a femur of an above-the-knee amputee. Asseen in FIG. 7 , the bone 502 may have an amputated end 504, and theresidual limb 500 may have a stump surface 506. A prosthetic limb orprosthetic limb attachment which may be attached to a residual limb 500may have problems fitting or functioning when attached to a residuallimb 500 having insufficient bone 502 length. The medullary canal 514 ofthe bone 502 may be drilled or reamed to a diameter about equal orslightly larger than that of the distraction device 110 to be utilized.The bone 502 may be divided into a first bone portion 508 and a secondbone portion 510 by creating an osteotomy 512. In FIG. 8 , thedistraction device 110 may be placed within the medullary canal 514 sothat the one or more holes 210 are within the first portion 508 and theone or more holes 208 are within the second portion 510. Duringpre-operative planning, members of the surgical team will often assessboth the condition and the coverage of soft tissues. The stump surface506 may be modified, by stretching the skin or tissue, or by adding skingraft material, or performing plastic surgery, in order to create enoughfuture available room for the bone 502 to increase in length inside theresidual limb 500 in the area adjacent the stump surface 506. Inaddition, infection prevention measures are commonly performed. Duringpre-operative planning, several other factors are determined including:the amount of limb length discrepancy, the diameter of the medullarycanal, the required length of distraction device 110 to be used, or thelocation of the planned osteotomy. In some cases, the distraction devicemay be implanted in an antegrade manner and in some cases in aretrograde manner. When implanted in an antegrade manner the distractiondevice 110 may be implanted via piriformis fossa entry. A retrogradeapproach may instead be chosen, for example, in patients with a severelyabducted hip. In FIG. 9 , bone screws 226, 224 are secured to the bone502 through the holes 210, 208 in order to secure the distraction device110 to the first and second bone portions 508, 510. The patient may beallowed to recover and at a later time, for example, about two to aboutten days or about five days, the first distraction procedure may beperformed. The ERC 180 may be placed on the residual limb 500 at alocation adjacent the magnet 338, and is operated to distract the firstbone portion 508 and the second bone portion 510 apart. The proceduremay be repeated several times and may be performed by medical personnel,or the patient's family and friends, or even the patient themself.Exemplary distraction protocol may include distraction of about 0.50 mmto about 1.50 mm in longitudinal distraction per day. In some cases, itmay include distraction of about 0.75 mm to about 1.25 mm inlongitudinal distraction per day. In some cases, the distraction may beabout 1.00 mm per day. This may be broken up into several distractionprocedures per day, for example, about 0.33 mm, three times a day.

FIG. 12 illustrates the distraction device 110 in the bone 502 after thesecond distraction rod 206 has approximately been fully distracted inrelation to the first distraction rod 204. Over the several weeks and/ormonths that the distraction procedures take place, a new bone growthsection 516 of bone begins to form between the first portion 508 and thesecond portion 510. FIG. 13 illustrates the distraction device 110 inthe bone 502 after the first distraction rod 204 has approximately beenfully distracted in relation to the housing 202. After the desired finaldistraction length is reached, distraction procedures are discontinued,and the new bone growth section 516 may be allowed time to fullyconsolidate. The distraction device 110 can continue to providestability to the bone 502 of the residual limb 500 while the bone 502 isallowed to consolidate and after the bone has consolidated. Afterconsolidation, the distraction device 110 may then be removed from thepatient, though in some cases, the distraction device 110 may be left inplace within the bone 502.

FIG. 14 illustrates one embodiment of a distraction device 600 placednext to a prior art distraction device 602. The distraction device 600may be capable of distracting about 50 mm, as is the prior artdistraction device 602, however the length L₁ of the housing portion ofthe distraction device 600 is over 25% percent shorter than the lengthL₂ of the housing portion of the prior art distraction device 602. Thetreatment of early onset scoliosis or adolescent idiopathic scoliosis isgenerally performed on small, thin patients having little space in theirsurgical sites to implant large device housings. Therefore, highefficiency adjustable distraction devices (total distraction length tohousing length ratio) may allow more patients to be treated. Turning toFIG. 15 , the distraction device 600 includes a housing 604 which may beconnected to a rod 606 by welding or other bonding methods. In someembodiments, the rod 606 and the housing 604 may be formed from the samemonolithic material. Within the housing 604, a driving element includinga magnetic assembly 608 (containing a radially-poled magnet 630) may beheld longitudinally stationary between a thrust bearing 610 and a radialbearing 612. Though gear modules may be incorporated, as in theembodiment of FIG. 1 , in FIG. 15 the distraction device is depicted inan embodiment wherein the magnetic assembly 608 may be directlyconnected to a first lead screw 614 by a pin 616. In the distractiondevice 600 embodiment of FIG. 15 , a first distraction rod 618 istelescopically carried on the outside of the housing 604, and islongitudinally displaceable along a longitudinal axis Z. A seconddistraction rod 620 may be telescopically carried within a cavity 622within the housing 604, and is longitudinally displaceable along thelongitudinal axis Z. The second distraction rod 620 has a cavity 632which allows space for the first lead screw 614. A second lead screw 624having an internal thread 626 at its proximal end 628 may be carriedannularly between the first lead screw 614 and the second distractionrod 620. Rotation of the magnetic assembly 608 by a remotely-appliedmoving magnetic field causes the first lead screw 614 to rotate withinthe internal thread 626 of the second lead screw 624, thus causing thesecond lead screw 624 and the second distraction rod 620 tolongitudinally displace in relation to the housing 604 and the firstdistraction rod 618. The distraction device 600 with the seconddistraction rod 620 fully displaced in relation to the first distractionrod 618 is illustrated in FIGS. 16-17 . At this fully displacedcondition, an abutment 634 at the distal end 636 of the first lead screw614 abuts a ledge 638 at the proximal end 640 of the second lead screw624. As the first lead screw 614 continues to turn, this causes thesecond lead screw 624 to turn in unison with the first lead screw 614,thus turning of the second lead screw 624 within an inner thread 642within the cavity 632 of the second distraction rod 620. This causes thesecond distraction rod 620 to longitudinally displace further from thehousing 604, dragging the first distraction rod 618 along with it. Thedistraction device 600 with the first distraction rod 618 fullydisplaced in relation to the housing 604 is illustrated in FIGS. 18-19 .A first o-ring 644 held in a circumferential groove in the firstdistraction rod 618 forms a dynamic seal between the first distractionrod 618 and the housing 604. A second o-ring 646 held in acircumferential groove in the first distraction rod 618 forms a dynamicseal between the first distraction rod 618 and the second distractionrod 620. The distraction device 600 may be capable of retracting, byapplying a moving magnetic field in an opposite direction, and causingthe components to turn in opposite directions.

The distraction device 600 may comprise features to limit or stoprotation between the first distraction rod 618 and the housing 604,and/or between the second distraction rod 620 and the first distractionrod 618. For example, the longitudinal grooves, 216, 220 and protrusions209, 211 of the embodiment of FIGS. 1-6 may be incorporated into thedesign of the distraction device 600, so that there may be substantiallyno rotation possible between the second distraction rod 620 and thehousing 604. For example, if the second distraction rod 620 is rigidlycoupled to a first vertebra (e.g., via a screw or hook) and the housing604 (e.g., via rod 606) is coupled to a second vertebra (e.g., via ascrew or hook), rotation may be substantially limited between the firstvertebra and the second vertebra, so that no unwanted movement betweenthem can occur. Furthermore, the abutments 289, 291, 293, 297 of theembodiment of FIGS. 1-6 may be incorporated into the design of thedistraction device 600 in order to control the extent of lengthening ofthe first distraction rod 618 in relation to the housing 604, and/or thesecond distraction rod 620 in relation to the first distraction rod 618.

FIGS. 20-23 illustrate embodiments of alternate sources to the rotatablemagnetic assembly as the driving element 242 of a non-invasivelyadjustable implant. FIG. 20 illustrates a non-invasively adjustablesystem 1300 comprising an implant 1306 having a first implant portion1302 and a second implant portion 1304, the second implant portion 1304non-invasively displaceable with relation to the first implant portion1302. The first implant portion 1302 may be secured to a first boneportion 197 and the second implant portion 1304 may be secured to asecond bone portion 199 within a patient 191. A motor 1308 may beoperable to cause the first implant portion 1302 and the second implantportion 1304 to displace relative to one another. An external remotecontroller (ERC) 1310 has a control panel 1312 for input by an operator,a display 1314 and a transmitter 1316. The transmitter 1316 sends acontrol signal 1318 through the skin 195 of the patient 191 to animplanted receiver 1320. Implanted receiver 1320 communicates with themotor 1308 via a conductor 1322. The motor 1308 may be powered by animplantable battery, or may be powered or charged by inductive coupling.

FIG. 21 illustrates a non-invasively adjustable system 1400 comprisingan implant 1406 having a first implant portion 1402 and a second implantportion 1404, the second implant portion 1404 non-invasivelydisplaceable with relation to the first implant portion 1402. The firstimplant portion 1402 may be secured to a first bone portion 197 and thesecond implant portion 1404 may be secured to a second bone portion 199within a patient 191. An ultrasonic motor 1408 may be operable to causethe first implant portion 1402 and the second implant portion 1404 todisplace relative to one another. An external remote controller (ERC)1410 has a control panel 1412 for input by an operator, a display 1414and an ultrasonic transducer 1416, which may be coupled to the skin 195of the patient 191. The ultrasonic transducer 1416 produces ultrasonicwaves 1418 which pass through the skin 195 of the patient 191 andoperate the ultrasonic motor 1408.

FIG. 22 illustrates a non-invasively adjustable system 1700 comprisingan implant 1706 having a first implant portion 1702 and a second implantportion 1704, the second implant portion 1704 non-invasivelydisplaceable with relation to the first implant portion 1702. The firstimplant portion 1702 may be secured to a first bone portion 197 and thesecond implant portion 1704 may be secured to a second bone portion 199within a patient 191. A shape memory actuator 1708 may be operable tocause the first implant portion 1702 and the second implant portion 1704to displace relative to one another. An external remote controller (ERC)1710 has a control panel 1712 for input by an operator, a display 1714and a transmitter 1716. The transmitter 1716 sends a control signal 1718through the skin 195 of the patient 191 to an implanted receiver 1720.Implanted receiver 1720 communicates with the shape memory actuator 1708via a conductor 1722. The shape memory actuator 1708 may be powered byan implantable battery, or may be powered or charged by inductivecoupling.

FIG. 23 illustrates a non-invasively adjustable system 1800 comprisingan implant 1806 having a first implant portion 1802 and a second implantportion 1804, the second implant portion 1804 non-invasivelydisplaceable with relation to the first implant portion 1802. The firstimplant portion 1802 may be secured to a first bone portion 197 and thesecond implant portion 1804 may be secured to a second bone portion 199within a patient 191. A hydraulic pump 1808 may be operable to cause thefirst implant portion 1802 and the second implant portion 1804 todisplace relative to one another. An external remote controller (ERC)1810 has a control panel 1812 for input by an operator, a display 1814and a transmitter 1816. The transmitter 1816 sends a control signal 1818through the skin 195 of the patient 191 to an implanted receiver 1820.Implanted receiver 1820 communicates with the hydraulic pump 1808 via aconductor 1822. The hydraulic pump 1808 may be powered by an implantablebattery, or may be powered or charged by inductive coupling. Thehydraulic pump 1808 may alternatively be replaced by a pneumatic pump.

Though not illustrated, another driving element 242 may include amagnetorestrictive element. A number of materials may be used to producethe components like the housing, first distraction rod, seconddistraction rod, first lead screw, and second lead screw, including butnot limited to titanium, titanium alloys, titanium 6-4, cobalt-chromiumalloys, and stainless steel.

FIG. 24 illustrates a sterilizable kit 700 of instruments for use withembodiments of the distraction device described herein. A sterilizabletray 702 includes holes 704 which may allow gas or steam to enter thetray 702 when the tray 702 is covered by a cover (not shown). One ormore dividers 706 may be constructed of a pliable material (such assilicone) and provide cavities, holes or slits therebetween for securingthe one or more instruments. A drill bushing 708 and a guide tube 710may be used for guiding one or more drills or reamers, for example,while drilling holes within the medullary canal of a bone. Prior tothis, a hole may be made in the skin, soft tissue, and/or bone using apiercing rod 730. Vent holes may be made in the bone prior to reaming inorder to avoid high intramedullary pressures which may cause fatembolism, or other complications, The medullary canal may in some casesbe reamed to a slightly larger diameter than the diameter of thedistraction device 110, for example 0.5 mm larger, or may be reamed 1 mmlarger or 2 mm larger. A guide arm 712 may be connected at a distal end713 of its guide tube 725 to a the housing 202 of the distraction device110 of FIG. 6 , for example an engagement portion 213 at the proximalend 221 of the housing 202. The engagement portion 213 may include acavity, for example, a threaded cavity, and may be engageable via adistal end 723 of a locking rod 722. The locking rod 722 may be insertedthrough the guide tube 725 of the guide arm 712. The locking rod 722 maybe tightened (or untightened) by turning a handle 727, or by placing atommy bar 718 through a transverse hole 729 at or near the handle 727 ofthe locking rod 722. The drill bushing 708 and a guide tube 710 may beplaced through transverse holes 735 in the guide arm, or a guideextension 724 may be secured to the end 737 of the guide arm 712. One ormore additional transverse holes 735 may be within the guide extensionfor placement of the drill bushing 708 and a guide tube 710. During themanipulation of the distraction device 110 with the instruments, softtissue of the patient may be protected with a soft tissue protector 714.Some or all of the cylindrical instrument components may be rotated withincreased torque by attaching a T-handle 716. If the distraction device110 and the guide arm 712 need to be removed, for example from a reamedmedullary canal in the bone, a mallet 720 may be placed so that a slit731 in the head 733 of the mallet 720 is around the guide tube 725 ofthe guide arm 712. The mallet 720 may be then caused to impact againstthe handle 727 of the guide arm 712 to aid in the removal of thedistraction device 110 and guide arm 712. After implantation of thedistraction device 110 and its securement to the bone by one or morebone screws, the guide arm 112 may be removed, by unscrewing the lockingrod 722 from the engagement portion 213 of the distraction device 110.

If the distraction device 110 is to be removed from the bone (forexample after the bone has been lengthened and allowed to consolidate),after the bone screws are removed, an extractor 726 may be attached tothe engagement portion 213 of the distraction device 110 and thedistraction device may be pulled out of the medullary canal by hand, ormay be hammered out using the mallet 731. The distal end of theextractor 726 may have a male or female thread that can be engaged withthe proximal end 221 of the housing 202 of the distraction device 110.An additional removal rod 728 may be used. Further instruments that maybe used include a locking key 732, a short impactor 734, a hexagonheaded river 736 and a locking driver 738. Bone screws 740 may besecured with a screw capture rod 740. Other instruments and uses ofinstruments are described in U.S. Pat. No. 8,449,543, which isincorporated herein by reference in its entirety.

Although this invention has been disclosed in the context of certainpreferred embodiments and examples, it will be understood by thoseskilled in the art that the present invention extends beyond thespecifically disclosed embodiments to other alternative embodimentsand/or uses of the invention and obvious modifications and equivalentsthereof. In addition, while a number of variations of the invention havebeen shown and described in detail, other modifications, which arewithin the scope of this invention, will be readily apparent to those ofskill in the art based upon this disclosure. It is also contemplatedthat various combinations or sub-combinations of the specific featuresand aspects of the embodiments may be made and still fall within thescope of the invention. Accordingly, it should be understood thatvarious features and aspects of the disclosed embodiments can becombined with or substituted for one another in order to form varyingmodes of the disclosed invention. Thus, it is intended that the scope ofthe present invention herein disclosed should not be limited by theparticular disclosed embodiments described above, but should bedetermined only by a fair reading of the claims that follow.

Similarly, this method of disclosure, is not to be interpreted asreflecting an intention that any claim require more features than areexpressly recited in that claim. Rather, as the following claimsreflect, inventive aspects lie in a combination of fewer than allfeatures of any single foregoing disclosed embodiment. Thus, the claimsfollowing the Detailed Description are hereby expressly incorporatedinto this Detailed Description, with each claim standing on its own as aseparate embodiment.

What is claimed is:
 1. An adjustable implant comprising: an actuatorlongitudinally restrained within a housing; a driver coupled to theactuator and configured to rotate at least partially within and relativeto the housing upon actuation of the actuator, wherein the driverincludes an external thread; a moveable member having an internal threadengaged with the external thread of the driver, wherein the movablemember is configured to move in relation to the driver and the housingupon rotation of the driver, wherein at least a portion of the moveablemember surrounds a portion of the housing such that, upon actuation ofthe actuator, the moveable member translates longitudinally along anexterior of the housing and the actuator is longitudinally fixed withrespect to the housing.
 2. The adjustable implant of claim 1, whereinthe driver is a lead screw.
 3. The adjustable implant of claim 1,wherein the actuator includes a magnet, a motor, a shape memoryactuator, an ultrasonic motor, or a hydraulic pump.
 4. The adjustableimplant of claim 3, wherein the actuator includes the motor.
 5. Theadjustable implant of claim 3, wherein the actuator includes the shapememory actuator.
 6. The adjustable implant of claim 3, wherein theactuator includes the magnet, wherein the magnet includes aradially-poled permanent magnet, and wherein the actuator is heldbetween a radial bearing and a thrust bearing, wherein the radialbearing and the thrust bearing are restrained at their respectivelongitudinal extents in relation to the housing.
 7. The adjustableimplant of claim 1, wherein the moveable member is configured to move ina first direction about the housing such that a length of the adjustableimplant increases and in a second direction about the housing such thatthe length of the adjustable implant decreases.
 8. The adjustableimplant of claim 1, further comprising: a rod configured to moverelative to the housing upon actuation of the actuator.
 9. Theadjustable implant of claim 1, wherein the rod is at least partiallydisposed within the moveable member.
 10. An adjustable implantcomprising: a first sleeve configured to be coupled to a first boneportion; a second sleeve configured to move in relation to the firstsleeve to change a length of the adjustable implant; an actuatorconfigured to be actuated by a remote control positioned external to theadjustable implant; and a driver coupled to the actuator and configuredto rotate at least partially within and relative to the first sleeveupon actuation of the actuator thereby causing the second sleeve to movein relation to the first sleeve, wherein the driver includes an externalthread, wherein the second sleeve includes an internal thread configuredto engage with the external thread of the driver, and the second sleeveis configured to translate longitudinally along an exterior of the firstsleeve upon actuation of the actuator, and wherein the actuator islongitudinally fixed with respect to the housing.
 11. The adjustableimplant of claim 10, wherein the driver is a lead screw.
 12. Theadjustable implant of claim 10, wherein the actuator includes a magnet,a motor, a shape memory actuator, an ultrasonic monitor, or a hydraulicpump.
 13. The adjustable implant of claim 12, wherein the actuatorincludes the motor.
 14. The adjustable implant of claim 12, wherein theactuator includes the shape memory actuator.
 15. The adjustable implantof claim 12, wherein the actuator includes the magnet, wherein themagnet includes a radially-poled permanent magnet, and wherein theactuator is held between a radial bearing and a thrust bearing, whereinthe radial bearing and the thrust bearing are restrained at theirlongitudinal extents in relation to the housing.
 16. The adjustableimplant of claim 10, wherein the moveable member is configured to movein a first direction about the housing such that a length of theadjustable implant increases and in a second direction about the housingsuch that the length of the adjustable implant decreases.
 17. Theadjustable implant of claim 10, further comprising: a rod configured tomove relative to the housing upon actuation of the actuator, wherein therod is at least partially disposed within the moveable member.
 18. Adistraction and retraction device comprising: a housing having anactuator positioned therein; a driver coupled to the actuator andconfigured to rotate at least partially within and relative to thehousing upon actuation of the actuator, wherein the driver includes anexternal thread; a moveable member having an internal thread configuredto engage with the external thread of the driver; and a rod at leastpartially disposed within the moveable member, wherein actuation of theactuator in one direction causes the rod to translate longitudinallyalong an exterior of the housing such that an overall length of thedevice increases, and wherein actuation of the actuator in another,opposite direction causes the rod to translate along the exterior of thehousing such that an overall length of the device decreases, and whereinthe actuator is longitudinally fixed with respect to the housing. 19.The distraction and retraction device of claim 18, wherein the actuatorincludes a magnet, wherein the magnet includes a radially-poledpermanent magnet, and wherein the actuator is held between a radialbearing and a thrust bearing, wherein the radial bearing and the thrustbearing are restrained at their respective longitudinal extents inrelation to the housing.
 20. The distraction and retraction device ofclaim 18, wherein the moveable member is configured to move in a firstdirection about the housing such that a length of the distraction andretraction device increases and in a second direction about the housingsuch that the length of the distraction and retraction device decreases.